The purpose of this training proposal is to provide opportunities to learn new, innovative research methods to study the Hypothalamic-Pituitary-Adrenal (HPA) axis system and how it relates to drug use in a prenatally drug exposed group of adolescents. By creating an internship and taking courses focused on salivary bioscience and the stress response, advanced statistical techniques, and drug dependence, and obtaining further training and mentorship geared towards professional development, this training grant offers the opportunity to become an independent research scientist. According to the toxic stress model, early life adversity (ELA) changes the way the brain and neuro-endocrine response functions. The toxic stress model posits that biological predispositions such as prenatal drug exposure (PDE) can alter the development of the brain and the neuro-endocrine response so that the HPA axis may be dysregulated. The main hormone produced by the HPA system is cortisol, and it is a major indicator of the stress response. Chronically elevated levels of cortisol can have deleterious effects on the brain, including deficits in memory, learning, stat regulating capacities, and socio-emotional development. Atypical cortisol patterns have been reported in children living in environments with ELA and are related to adolescent drug use. Very little is known about the interplay between PDE, ELA, the HPA system, and drug use. The proposed research integrates biological, social, and psychological elements, and human development research increasingly requires this approach. The training plan allows for development and integration of these areas and application to an area of research that is now beginning to gain attention because of the far-reaching implications of the stress response (e.g., mental and physical health). The training and research plan achieve NIDA's goals of bringing science to bear on drug abuse and addiction by 1) examining the association between PDE and adolescent drug use and how they both directly and indirectly relate to HPA axis regulation and2) by conducting research across a broad range of disciplines (biological, social, developmental, and psychological sciences).